1. Field of the Invention
The present invention relates to a water-soluble double-faced adhesive tape which is used for splicing paper etc. in paper mills and printshops.
2. Description of the Prior Art
The splicing of roll paper in paper mills and printshops has conventionally been accomplished by the aid of ordinary water-soluble double-faced adhesive tape which consists of a substrate, adhesive layers covering entirely both sides of the substrate, and release paper covering the adhesive layers. This adhesive tape suffers the disadvantage of requiring the operator to peel the release paper from it before its use. Peeling is troublesome, and the release paper is often broken during peeling, particularly in the case of splicing wide webs. Moreover, peeled release paper has to be disposed of as a bulky waste material.
Since paper webs undergo surface treatment (such as clay coating) by a knife coater or supercalendering for finishing in paper mills to make a thickness of paper even, their splicing in the conventional manner (as shown in FIG. 3) poses a problem associated with web feeding. That is, the spliced part is too thick to pass smoothly at a high speed through the gap of the knife coater or calender roll which is adjusted to the thickness of a single web. There often occurs breakage at the spliced part. Therefore, the conventional overlap splicing is unfavorable particularly for thick webs.
For reasons mentioned above, it has been believed that the double-faced adhesive tape for splicing webs in paper mills should be as thin as possible. However, there is a certain limit to reducing the thickness of the adhesive layer while maintaining an adhesive force for practical use.